Text input of electronic devices mainly can be divided into two classes, namely handwriting input and keyboard input, while some devices can support input by touching touch screen to select, which is substantially using the screen area as a virtual keyboard, and is also an idea of keyboard input. For keyboard input, inputting by a standard full keyboard, such as a computer keyboard, a PDA keyboard or a smartphone keyboard, can be considered as the most feature-complete keyboard. However, a full keyboard requires large space, and then it has some limits in using. Therefore, many input methods have been developed with keyboards with limited keys, wherein a method for text input with a digital 12 key 4-by-3 keypad is most typical. With the popularity of phone products, methods for text input with keypads have been developed dramatically. Unfortunately, there has never been a better solution to reduce key ambiguity. On average, the keys almost have to be pressed for three times to input a character when the input object is not a morpheme but a character (Morpheme here stands for an ideographic linguistic unit, e, g. “” in Chinese or “word” in English.)
Some devices with limited panel space, like e-book readers, and media players such as MP3, and MP4, usually are equipped with some arrow keys and a confirmation key and without numerical keys. Even more, a computer is needed to connect with said devices for text input by the computer, which is quite inconvenient. For example, people may need to add some bookmarks annotations while they are reading the e-books, in this case, it is quite essential to using the readers for text input. As we know, the full keyboard is a solution to this problem, as Kindle reader, the best seller produced by Amazon, is mostly equipped with a full keyboard. However, the full keyboard has its own limits—occupying more space, which would need to increase the size of reader or decrease the size of screen. What's worse, the corresponding devices including hardware such as a key scanning circuit and an inputting keyboard will cost amore. An ideal product allows inputting text directly by a few keys, such as arrow keys base on the existent product. As a matter of fact, such inputting method doesn't exist in existent technologies.
The PCT application, with publication number of WO2006073273A1, title of “Method and apparatus for inputting character through direction input unit”, relates a input method having direction buttons. With this method, a mapping relationship between the sequence of the keys of the direction buttons and the keys of a 12-key 4-by-3 keypad is established to input by the direction buttons. For example, the sequence of any two direction buttons corresponds to one of the keys of 12-key keypad. In fact, this method is still based on the mapping relationship between the existing keypad and the corresponding character input. The difference is to establish the corresponding relationship between the direction buttons and the keypad. Therefore, for a character to input, if the average number of keystrokes by the keypad is 3, and then, the method mentioned in this PCT application will doubles the number of the times of pressing keys. So, the efficiency of this method is not high. What further affects of the use of this method is the requirement for user's good memory on the corresponding relationship between the characters of the keypads and the direction button sequences, which is quite inconvenient to ordinary users.
The U.S. Pat. No. 6,567,072, named as “Character input device and method”, discloses a character input method having a direction indicating device, a key input means and a display screen. Wherein the direction indicating device works as a rotation plate for outputting the inclination angle and its force; a control means receives radial and circumferential position information output by the direction indicating device; the screen displays depending on the radial information and the corresponding relationship between the output stored in it and the character sets; then, a single character in the character set displayed on the screen is selected depending on the circumferential information; finally, the selected character is determined by the input of the key input means. However, this input method has higher demand on the direction indicating device, which not only can locate a plurality of directions on the circumference, but also can locate different radius on every circumference. Such requirements make its structure more complicated, and at the same time, it leads to a higher hardware cost and lower durability. Obviously, this method does not make universal performance for existing ordinary key pressing device.
Hence, the current technology on input device and method is inapplicable to electronic devices for text input with a few key buttons, such as e-hook, MP3 and MP4.